It sounds a good idea but I think that sometimes we can give a customer too much information.
Some gutters are free running and other's aren't. What does your customer think when he/she sees a video of you cleaning and charging for a virtually clean gutter, even if the gutter on the other side of the house was chock-a-block?
If you do send a copy to a customer, then I would tend to send it of the end result rather than of it actually happening.
But not having this equipment doesn't make me an expert in these matters, its just an opinion.
